The invention relates to a wearing ring, particularly for the protection of a cable guide hose on a robot, with an inner ring and an outer ring in each case having two half-shells, as well as a robot equipped with a cable guide hose having at least one such wearing ring.
Cable guide or protection hoses or tubes are mainly used on machines, particularly robots having several parts pivotable relative to one another in order to guide outside the robot electric cables for the power supply of the robot or a tool located in a robot hand. During operation distance changes occur between individual points of the robot, so that the cable guide hose is exposed to mechanical wear particularly at locations where movable robot parts, such as a rocker arm, a robot arm or a robot hand can be in contact and there is a risk of chafing or fraying. In order to avoid hose damage as a result of chafing or fraying, it is known to locate at such critical points of the cable guide hose wearing rings, which are in turn frayed and subsequently replaced.
Wearing rings generally comprise two half-shells, which are interconnected by means of countersunk screws. If the wearing ring becomes frayed in the vicinity of the screw fastening, the countersunk heads of the screw project and can then damage machine or robot parts along which the wearing rings and consequently the projecting screw heads rub.
DE 298 14 418 U1 describes a wearing ring according to the preamble of claim 1, in which the half-shells of the inner ring are connected in either fixed manner or by frictional resistance to the half-shells of the outer ring. The outer and inner rings have different colours, so that after the outer ring has become worn, the colour of the inner ring is detectable and consequently indicates that the wearing ring must be replaced. For joining the half-shells use is made of plastic screws, which engage in a tapped hole located on the face of the second half-shell facing the first half-shell of the wearing ring. For fitting the screw the first half-shell has a hole which passes through it and which is aligned with the tapped hole of the second half-shell.
The relatively complicated and expensive manufacture of the tapped hole, e.g. through an additional part having the tapped hole and injection moulded into the given half-shell and the assembly and disassembly of the wearing ring with respect to the cable guide hose require the use of special tools constitute disadvantages.
The problem of the invention is to so further develop a wearing ring of the aforementioned type in such a way that it can be less expensively manufactured and can consequently be more easily and rapidly fitted and dismantled.
According to the invention this problem is solved by a wearing ring of the aforementioned type, in that the half-shells of at least one of the rings can be locked together.
As a result of the construction according to the invention on the one hand a simple, inexpensive, one-piece manufacture of the half-shells in a single process is possible and in the case of a plastic wearing ring more particularly by extrusion. On the other hand no tools are required for fitting the wearing ring to a cable guide hose, in that the half-shells of the wearing ring are not screwed together, but instead merely placed on the hose and locked together.
Advantageously in each case one half-shell of a ring is lockable by means of a tongue located on the face facing the other half-shell of this ring in a recess located on the face of the other half-shell of said ring and for releasing the tongue from the recess there is a hole connecting said recess of said half-shell to the outer circumference thereof. Thus, for the disassembly of the two half-shells of the ring it is merely necessary to have a substantially pin-like accessory, which is inserted into the hole located on the outer circumference of the half-shells in order to release the tongue from its locking position in the recess.
Preferably each half-shell of a ring on its face facing the other half-shell of said ring is equipped with the tongue and on its other face facing the other half-shell of said ring with the recess having the hole, so that both half-shells have an identical construction and consequently manufacturing costs are minimized. For reasons of easy accessibility during the release of the half-shells of the ring by inserting a substantially pin-like accessory into the hole linking the outer circumference of the half-shell with the recess in order to disengage the tongue from the recess, the hole preferably traverses the half-shell substantially perpendicular to the recess.
In order to prevent a release of the half-shells of the wearing ring according to the invention in reliable manner as the chafing of the outer ring progresses, preferably the half-shells of the inner ring can be locked together.
If in this case the half-shells of the inner ring are lockable in particular by means of a tongue located on at least one face facing the other half-shell of the inner ring in a recess located on the face of the other half-shell with a hole linking the recess with the outer circumference of the half-shell, the half-shells of the outer ring preferably have a radial hole aligned with the hole connecting the recess with the outer circumference of the half-shells of the inner ring. In this way the half-shells of the inner ring can be easily detached from one another without removing the outer ring from the inner ring, in that a pin-like accessory is introduced through the radial hole of the outer ring into the hole in the inner ring, in order to disengage the tongue from the recess.
In order to solve the problem of the invention, in the case of a wearing ring of the aforementioned type the half-shells of the outer ring can be locked with the half-shells of the inner ring.
As a result of this construction no tools are required for fitting the half-shells of the inner ring to the half-shells of the outer ring in that the latter are locked with the half-shells of the inner ring by pressing thereon and can be fixed thereto in positive manner.
The half-shells of the outer ring are preferably fixable by means of internally positioned detents on complimentary locking depressions provided on the outside of the half-shells of the inner ring, so that on pressing the half-shells of the outer ring onto the half-shells of the inner ring, the detents engage in the locking depressions, which can in particular be ensured by undercuts of the locking depressions in which engage the complimentary detents. Alternatively or additionally, it is obviously possible to fix the half-shells of the inner ring by means of externally located detents on complimentary locking depressions provided on the inside of the half-shell of the outer ring.
The detents and locking depressions are preferably placed in each case in the vicinity of the ends of the half-shells and preferably in the region of the ends of the half-shells in each case two axially spaced detents or locking depressions are arranged in circumferentially succeeding manner. Thus, the half-shells of the outer ring are securely and reliably fixed to the half-shells of the inner ring in the vicinity of the facing ends.
For releasing the half-shells of the outer ring from the half-shells of the inner ring, on the face of the half-shells of the inner ring on the side facing the half-shells of the outer ring a break is preferably provided and by inserting an accessory, e.g. a screwdriver, ensures a simple and rapid release of the half-shells by disengaging the detents from the locking depressions. Alternatively or additionally and for the same purpose, it is obviously possible to provide a break on the faces of the half-shells of the outer ring on the side facing the half-shells of the inner ring.
In a preferred development, on the outside of the half-shells of the inner ring and on the inside of the half-shells of the outer ring are provided complimentary centring devices, which are e.g. formed by at least one circumferentially positioned circumferential projection on the outside of the half-shells of the inner ring and at least one circumferential groove located on the inside of the half-shells of the outer ring or by at least one circumferentially positioned circumferential projection on the inside of the half-shells of the outer ring and at least one circumferential groove located on the outside of the half-shells of the inner ring. Preferably there are two circumferentially positioned circumferential projections and two circumferential grooves complimentary thereto.
In a further development of the wearing ring according to the invention, on facing faces of the half-shells of at least one of the rings are provided centring means, so that frontally contacting half-shells are perfectly aligned. The centring means are preferably located on the faces of both the outer and the inner ring.
The centring means are preferably in the form of at least one projection located on at least one face of the half-shell of one ring and at least one complimentary depression located on the face of the other half-shell of said ring facing the first face, so that the projection located on one face of the half-shell of said ring in each case engages in the complimentary depression provided on the face facing the same of the other half-shell of said ring. In order to ensure the same structure of the two half-shells of the inner and outer ring, preferably each half-shell of the particular ring, preferably on its face facing the other half-shell of said ring, is provided with at least one projection and on its other face facing the other half-shell of this ring with at least one complimentary depression.
In another advantageous construction, the half-shells of the inner ring are provided on the inside with circumferentially passing ribs for fixing on a ribbed cable guide hose. There are in particular at least four ribs, so that the wearing ring can also be used for joining two hose portions of the cable guide hose, which are in each case held by at least two of the inside ribs of the wearing ring. This makes it possible to use the wearing ring according to the invention as a coupling sleeve for several hose portions, e.g. when using hose portions with different elasticity.
It is particularly advantageous to design the ribs in such a way that at least some ribs project from the face of one half-shell of the inner ring and the ribs of the other half-shell of the inner ring aligned with the projecting ribs of one half-shell are correspondingly recessed, so that said ribs, apart from fixing to the cable guide hose, are additionally used for centring the two half-shells of the inner ring. In order to obtain a unitary construction, preferably each half-shell of the inner ring is equipped on its face facing the other half-shell of the inner ring with at least two projecting ribs, whilst the same ribs are correspondingly recessed on their other face.
As has already been indicated, both the inner and outer rings are preferably made from plastic, whereby the inner and outer rings are in particular made from different coloured plastics, so that following the wearing of the outer ring the colour of the inner ring can be detected and in this way the necessary replacement of the wearing ring is indicated. The inner ring is appropriately provided with a conspicuous colour, e.g. signal red, signal yellow, etc.
The invention also relates to a robot equipped with a cable guide hose having at least one wearing ring of the aforementioned type.